'The Ballad of Filthy Muck' is a loose remake of 'The Thing', where Squidward gets covered in cement while fleeing from SpongeBob and Patrick, is partially paralyzed from the cement and is unrecognizable to everyone.
In Hocus Pocus: Spongebob thinks that "Mr. Magic" will help him return Squidward to his original form. Along the way Spongebob says "Just follow the brown tile road to the most mysterious mystic of them all - no one has ever seen him in person". Inside the building is a giant floating head with a booming voice, but Patrick notices a normal fish behind a curtain. The whole scene is very similar to the scene in "The Wizard of Oz" when Dorothy finds out about the real wizard.